How can you optimize ActiveMQ broker performance?

Several concrete levers help ActiveMQ handle more load without adding hardware:

• Lower the consumer prefetch limit for slow consumers so one client can't hoard a large batch of messages.
• Use asyncSend for messages that don't need a synchronous broker round-trip.
• Prefer KahaDB over JDBC persistence for local disk speed unless shared storage is required.
• Split high-volume non-persistent traffic onto separate connectors/destinations from critical persistent traffic.
• Tune the JVM heap and use the NIO transport for many concurrent connections.

It also helps to right-size the number of consumer threads relative to available CPU cores, since too many competing consumer threads can cause contention rather than added throughput. Monitoring the destination's memory usage percentage in the web console over time helps catch a slow-building backlog before it triggers flow control, and periodically reviewing KahaDB's data log file count can reveal whether cleanup is failing to keep pace with incoming persistent traffic, which itself can quietly degrade performance over weeks.